LA-8036-PR Progress Report ClC-l 4 REPORT COLLECTION C3● REPRODUCTION COPY Applied Nuclear Data Research and Development April l—June 30, 1979 J (s!!likLOSALAMOSSCIENTIFICLABORATORY Post Office Box 1663 Los Alamos. New Mexico 87545 AnAffirmativeAction/EqualOpportunityEmployez Thefourmostrecentreportsinthisseries,unclassified, areLA-7482-PR,LA-7596-PR,LA-7722-PR,and LA-7843-PR. ThisreportwasnoteditedbytheTechnicalInformation staff. Thisworkwasperformedundertheauspicesofthe USDepartmentofEnergy’sOfficeofMilitary Application,DivisionofReactorResearchand Technology,OfficeofBasicEnergySciences,andOffice ofFusionEnergy;andtheElectricPowerResearch Institute. l%is r.purt wasprep. red .s an account of umtk sponsored by the United SlaLesG..mmmnt. Neither the United Stat.. north. United S,.1,s Cwmrtmmt of Ene,,y. nor .ny of Ihei, ●mployees. nor .ny of them mmractors. s. bcontr.ctors, m their ●mployees. makes my warranty. express c.. implied. or assume, any 1.”1 Imbibty or mswnsib,!ity 10, the .CCU,XY. completeness.-orusefulness of my information, .IXMr.t.s. product. or Processdisclosed. or r.uresents th.t i- ust would not in frlnze ptiv.lely owned rights. UNITED STATES DEPARTMENT OF ENERGY CONTRACT W-740 B-ENG. 36 I LA-8036-PR ProgressReport UC-34C Issued: September 1979 Applied Nuclear Data Research and Development April l—June 30, 1979 C. 1. Baxman P. G. Young I r-- I ,. .. ,-. —— CONTENTS I. THEORYAND EVALUATIONOF NUCLEARCROSS SECTIONS 3 A. 6Li(p,He) Cross Sections..................... 1 9 B. n+ Be Evaluation......... 3 c. ArsenicCalculations.......................... 3 D. Erratum:Calculationof Neutron-InducedCross Sectionson Isotopesof Iridium............... 8 E. AverageNeutronicPropertiesof “Prompt” FissionProducts........● *.................... 8 F. GNASH Improvements............................ 12 G. CSEWGActivities.............................. 13 II. NUCLEARCROSS SECTIONPROCESSING A. Cross SectionProcessing...................... 14 B. EnergyBalanceof ENDF/B-V.................... 14 c. An EpithermalDisadvantageFactorfor EPRI-CELL● ......0. ....00.0. 17 III. FISSIONPRODUCTSAND ACTINIDES: YIELDS,YIELD THEORY, DECAYDATA, DEPLETION,AND BUILDUP A. FissionYield Theory.......................... 19 B. ENDF/B-VFissionProductYieldsand Testing... 19 c. The Effectsof NeutronAbsorptionon Decay Heat.................. 22 D. Decay Data Testingfor ENDF/B-V............... 28 E. AND 5.1 Decay Power Standard.................. 29 F. ThreeMile IslandCalculations................ 31 Go Decay SpectralComparisons.................... 35 H. CINDER-10Code................................ 35 REFERENCES......00 ..0.00.0. 35 iv APPLIEDNUCLEARDATA RESEARCHAND DEVELOPMENT QUARTERLYPROGRESSREPORT April 1 - June 30, 1979 Compiledby C. I. Baxmanand P. G. Young ABSTRACT This progressreportdescribesthe activitiesof the Los AlamosNuclearData Group for the periodApril 1 through June 30, 1979. The topicalcontentis summarizedin the contents. I. THEORYAND EVALUATIONOF NUCLEARCROSS SECTIONS 3 A. 6Li(p,He) Cross Section[G.M. Hale; D. C. Dodder;and S. D. Baker and E. K. Biegert (RiceUniversity)] The 6Li(p,3He)reactionis of interestat very low energiesin connection 6 with astrophysicalquestionsabout the relativeabundancesof Li and 7Li and recentlyhas been receivingattentionat higherenergiesas a possibleexotic fuel for fusionenergyapplications.Reliableintegratedcross sectionsfor this reactionhave been difficultto obtainin view of discrepanciesas largeas 50% among the measurements. Predictionsfor this crosssectionhave been availablefor more than two 7 years from our multichannelR-matrixanalysesof reactionsin the Be systemand 7 7 charge-independentanalysisof reactionsin the Be and Li systems. These re- suitshave been describedin part in previousprogressreports1-4 and at the Har- 5 well Conference. Since the experimentalcross-sectiondata includedin the anal- ysis for the 6Li(p,3He)reactionrequiredextensiverenormalizationin almost every case,we have been uncertainabout the reliabilityof the scale of our cal- culatedcross sections,which presumablywas determinedby data for other reac- 4 6 7 tions in the analysis[e.g., He(3He,3He)4Heand Li(p,p)6Liin the Be analysis]. 6 Recently,new absolutemeasurementsof Li(p,3He)4Heangulardistributions 6 at protonenergiesbetween0.14 and 3 MeV have been made by Elwynet al. at Ar- gonneNationalLaboratory. A comparisonof theirintegratedcross sectionswith our predictionsis shown in Fig. 1. It can be seen that the agreementof the calculationswith the new measurementsis excellent,both in shapeand magnitude. The agreementof the calculatedangulardistributionswith the new data6 is gen- erallygood at energiesbelow 1.5 MeV; above that energy,interferenceeffects 6 with p- Li d-waves, whichwere neglectedin the calculation,appearto prevent good agreementwith the measuredangulardistribution,althoughthey have no effecton the integratedcross sections. This comparisonindicatesthat the other7-nucleondata in the analyses, throughunitaryand charge-conjugaterelationships,correctlydeterminedthe 6 3 7 scaleof the Li(p, He) reactioncrosssection,much as other Li data had con- 6 strainedvaluesof the Li(n,t)cross sectionin the analysis7used for the ENDF/B-V6Li evaluationat low energies. A paper8reportingvaluesof the low- energycrosssectionsand an expressionof the astrophysicals-functionhas been submittedto AstrophysicalJournal. 6LI [P, 3HEI 4HE m.+ o 5& cu_ f ~ o z -(CJo k o- $ V)m 02;- Cn 0 l% IT c)?3_ o ~ o + ELWYN ET f7L. 1979 8 0 1 I I I I 1 0.0 0.4 0.8 12 1.6 2.o 2.4 ; s PROTON ENERGY (MEV) Fig. 1. Predictionsfrom the charge-symmetric7-nucleon analysis5comparedwith recentmeasurementsof Elwyn et al.6 for the 6Li(p,3He)4Heintegrated crosssection. 2 9 B. Xl+ Be Evaluation (P. G. Young and L. Stewart) n A report’has been writtendescribingthe Los AlamosScientificLaboratory -5 (LASL)evaluationof n + ‘Be reactions, which coversthe energyrange 10 eV to 20 MeV. In the evaluationparticularemphasiswas placedon accuratelyrepresent- 10 ing new measurementsof secondaryneutron-emissionspectra and scatteringdata 11 between6 and 15 MeV. Additionally, adjustmentsto the total,(n,y),and (n,t) cross sectionsfrom previousENDF/Bevaluationswere made, and covariancedata filescontainingerrorcorrelationsfor crosssectionsand emissionspectrawere obtained. Detailedcomparisonsof experimentaland evaluateddata are presented in the report,and the new evaluationis found to representthe neutronemission 10 spectradata much more accuratelythan ENDF/B-V. The evaluateddata are avail- able in ENDF/Bformatfrom the ENDF/Alibraryat the NationalNuclearData Center at BrookhavenNationalLaboratoryand from the RadiationShieldingInformation Centerat Oak RidgeNationalLaboratory. c. ArsenicCalculations(E. D. Arthur) 74,75 Calculationsof neutron-inducedreactionson As isotopeshave been made in the energyrangebetween0.001and 20 MeV. The reactionsfor wh:Lchcross sec- tionswere calculated,theirQ values and thresholdsare given in Table I. For 12 this effort,a similarapproachto that used for our n + Y calculat:Lonswas fol- lowed. That is, independentdata [neutrontotalcrosssections,resonanceparame- ters,and (p,n)results]were used in a determinationof consistentsets of neu- tron and protonopticalmodel parameters. For example,Fig. 2 comparesour cal- 75AS culatedtotal cross sectionto experimentaldata for n + . The neutronop- ticalparametersappearin Table II. For ~ As, the (n,np)thresholdis about 3.5 MeV lower than that for the (n,2n)reaction. This leads to an incidentenergyregionin which the total protonproductioncross sectioncan be sensitiveto the parametersused to de- scribelow energyprotonemission. Therefore,we used a protonopticalparameter set similarto that from our n + Y calculationsand adjustedit slightlyto pro- 74 duce agreementwith low-energy(p,n)measurements.In Fig. 3, Ge(p,n)cross sectionscalculatedwith theseparametersand the neutronparametersof Table III 13 are comparedto experimentaldata of Johnsonet al. Along with both neutron and protonparameterdeterminations,the gamma-raystrengthfunctionwas obtained 75 throughfits to As capturedata. 3 TABLE Q VALUESAND THRESHOLDS + As REACTIONS E~h (MeV) —MT Reaction Q @fev) 74 74A8 74As 4 As(n,n’) -0.173 0.175 74 73AS 16 As(n,2n) -7.977 8.086 74 73nlAs 16 As(n,2n) -8.475 8.59 74 7oGa 22 As(n,na) -4.378 4.437 74 73Ge 28 As(n,np) -6.854 6.948 74 102 As(n,y)75As 10.243 0. 74 75mAs 102 As(n,y) 9.939 0. 74 103 As(n,p)74Ge 3.346 0. 74 70,71Ga 107 As(n,ct+ n,an) 4.926 0. 75AS 75 75AS 4 As(n,n’) -0.198 0.201 75 74AS 16 As(n,2n) -10.243 10.38 75 17 As(n,3n)73As -18.22 18.465 75 71Ga 22 As(n,nCX) -5.316 5.39 75 74ce 28 As(n,np) -6.896 6.989 75 75mAs 54 As(n,nl) -0.304 0.308 75 76As 102 As(n,y) 7.33 0. 75 75Ge 103 As(n,p) -0.407 0.413 75 75mGe 103 As(n,p) -0.547 0.554 75 71,72Ga 107 As(n,a+ n,c%n) 1.205 0. 9.0I I I I 1 1 1 I 1 I I I I I I I 1 I I I t 7.0– v 6.0– - n 5.0– b 4.0– 3.0– a. 2.0 [ I 1 I I 1 Y 1 I II I t I t t 1 9 11 I I 0.1 1.0 10.0 20.30. NeutronEnergy(MeV) Fig. 2. Fit to the 75As totalcross sectionusing the parametersof Table II. TABLE II n + 75As NEUTRONOPTICALPARAMETERS Strength(MeV) r (fro) a (fro) v= 49.96- 0.4E 1.236 0.6 W (SaxonDerivative) =7.8 - O.llE 1.26 0.69 = 6.2 1.12 0.47 ‘so 1“’’1” 1’1’’” o. - a b 74Ge(p,n) 0.0 o O.oc 1 I $ f I I 1 I I I I 1 * 1 1 3.0 4.0 5.0 6.0 Proton Energy (MeV) Fig. 3. The 74Ge(p,n) crosssectioncalculatedwith the protonopticalparametersof Table III is com- pared to the resultsof Johnson.13 TABLE 111 PROTONOPTICALPAIUMETERS USED IN n + As CALCULATIONS Strength(MeV) r (fro) a (fro) v = 63.8 - 0.32E 1.225 0.665 w (SaxonDerivative) 3.0 + 0.6E